1. Field of the Invention
The present invention relates to the field of synchronizing asynchronous signals and finds particular use in synchronizing multiple video type signals in television systems.
2. Description of the Prior Art
The prior art contains many circuits for video synchronizers, beginning with U.S. Pat. No. 4,018,990. These synchronizers generally provide video synchronization by sampling and digitizing the active video portion of a video signal in response to the timing thereof, or in the case of digital video signals recovering the clock and digital samples therefrom, storing the digitized video in a memory. The digitized video is read from the memory at a proper time in response to a reference signal to achieve synchronization thereof. In some devices the digitized video is converted back to a more desirable form, digital or analog or both. Some devices reconstruct and combining the appropriate ones of sync, burst and blanking with the read video.
Video synchronizers for use with single video signals are commonplace in the industry, with multiple video signals being accommodated by use of multiple complete video synchronizers, each being fully self contained. Various techniques and circuits to perform these functions are well known in the art, and emphasis has been placed on improving performance in terms of minimizing noise and distortion from the digitizing process, and improving the immunity of the devices to noise or errors which may be carried with or interfere with the signal which is being synchronized.